SPRINGFIELD, Ill. — The largest public employee union in the state of Illinois recently has called for Gov. Pat Quinn to avoid selling the Thomson Correctional Center, just north of Thomson, Ill. and use it to ease overcrowding in other Illinois prisons.

The Quinn administration has set December 21 as the date the prison will be auctioned off in Chicago.

The prison was once targeted for Guantanamo Bay terrorism suspects. The Illinois Department of Corrections says it is housing nearly 48,000 inmates in space designed for approximately 34,000 inmates, meaning the system is operating at 148 percent of its designed capacity.

The state’s prison population has surged by 3,000 inmates in recent months with the governor’s suspension of good-time credits that enabled prisoners to cut short their prison sentences with good behavior.